Folding and fixing of composite blanks



Dec. 16, 1941 ER 2,266,459

. FOLDING AND FIXING OF COMPOSITE BLANKS Filed March 20, 1940 INVENTOR:

ATTORNEYS.

Patented Dec. 16, 1941 FOLDING AND FIXING OF COMPOSITE BLANKS Alfred G. Gilbert, South Acton, Masa, assignor to Reece Folding Machine Company, East Cam bridge, Masa, a corporation of Maine Application March 20, 1940, Serial No. 324,920

1 Claim.

This invention relates to the folding and fixing of composite blanks, having reference to blanks that'are laminated or composed of sheet materials, including fabric or similar limp facing and lining plies, which are mutually attached and combined by a cement. Such. composite material is widely used for the production of certain articles such as pocketbooks, wallets and other cases and small articles of various sorts. The sheet material may consist of an ornamental or quality facing such as woven silk, rayon or the like, with a backing or strengthening lining of less expensive material such as buckram, gauze or the like, the combined materials giving a desirable weight and strength not afforded by the more expensive or facing material alone. The usual cement by which the plies are bonded or preattached is one which is solid at normal temperatures but becomes liquid and flowable under suitable heat. It may be of a gelatinous or plastic character, although other kinds of cement are suitable for attaching together the two plies. The invention is applicable to any laminated fabric bonded by an adhesive that flows when hot.

A problem arises in the folding and fixing of blanks of such composite material in the manufacture of various articles therefrom. The actual folded blank for use in a commercial product. For these reasons the commercial types of folding machines and methods, although excellent for their mechanical performance, have never come into extensive practical use in the special field mentioned.

The general object of the present invention therefore is to provide a method and means for folding composite blanks, and fixing their folds, which will avoid the objections noted and will afford an accurate and reliable system of manufacture of folded composite blanks with high output and low cost of production. A particular ober, causing these parts to become sticky and tend folding of course can be done manually or mechanically, for example by means of apparatus or automatic machines which comprise a platen or bed to support each blank during folding, a templet for defining the fold, and a folder or in-' folder movable relatively to the templet to "perform the folding, in an arrangement in which the templet can be extracted from the fold, and the folded material then squeezed under pressure between the platen and folder to press and crease the fold. It is desirable that the folded part, margin or infold of the blank be caused to adhere against the body of the blank, so that the folded blank will reliably retain its condition until subsequent stitching or other operations, and the cement which is present in the contiguous lining portions is potentially available to aid in the adherence of the infold to the body. However, if

the folding and pressing are performed cold, then the cement will be inoperative as an adhesive between the fold and body. In automatic folding machines it is quite common to maintain highly heated the parts which act upon the blank, but if that plan be followed. with the composite blank then the facing becomes hot which rests upon the heated bed, and this, combined with the heat from the opposing folder renders the cement unduly liquid and fluent. It is found that the heat-softened cement tends to flow toward the source of heat, so that in the case mentioned the adhesive flows through the lining and into the facing of the body of the blank, thereby soiling or staining it to exterior view and spoiling the to pull the folded product out of shape in removing it from position; or may get on to the templet which then, in its retraction, disturbs the blank.

Other and further objects and advantages of the invention will be explained in the hereinafter following description of an illustrative embodiment thereof or will be understood by those conversant with the'subject.

Considered as a method ofinfolding and fixing a blank of composite sheet material with the aid of platen, templet and folder, the present invention may be described as comprising the following steps. The bed or platen is kept at such a cool temperature as to maintain solid or nonflowable the cement by which the plies, layers or. laminations are attached together, while on the other hand the folder or infolder is kept at such a warmer temperature asto render liquid or flowable the cement, preferably to a viscous or gummy consistency. Having established the predetermined respective temperatures for the bed and the folder, within suitable ranges, the operations upon each blank are commenced by placing the blank between the cool bed and the templet, with the facing ply of the blank toward the bed and its lining side defined by the templet to give the desired contour of folded blank. Having so defined the supported blank the next step is to move the folder relatively to the templet (the templet itself might be moved under the folder) in order to fold a portion of the blank, as to infold a margin thereof, over the edge of the templet, thus producing the desired fold; thereupon relatively extracting the templet from the fold, leaving the blank fold or infold between the bed and folder, having differential temperatures as mentioned. Thereupon the blank fold is squeezed between the cooler bed and the warmer folder for a brief period of pressure; the duration and pressure being sufficient to crease the fold edge and tocause its folded portion or margin to adhere to its body with the aid of the heat-softened and liquefied cement which is present in the two portions of the lining ply. The duration and pressure however are insuflicient to permit appreciable flow of the softened cement through or from the lining into the facing of the blank. By the steps thus described the facing exterior is protected by the cooler temperature of the bed from being soiled or stained by the cement, as would frequently be the case were the bed not maintained at the differentially cooler temperature. After these actions the pressure is relaxed and the complete blank is removed and laid aside for subsequent stitching operation. The cement, not being heated for excessive fluidity, can not reach the appliances, the platen, the folder orthe templet,

which otherwise would become sticky and impair the operations. The relative movements of bed, templet and folder may be performed automatically, under power operation, and following the removal of each completed blank a new unfolded blank may be presented to the mechanical elementsand the steps repeated,'for each subsequent blank, for quantity production of folded blanks of high quality and accuracy.

The method hereof is best expressed by reference to the apparatus elements or appliances used in its performance, but in an abstract aspect may be considered irrespective thereof. Moreover, since the conventional apparatus and appliances are specially operated the invention may also be viewed as involving novelty of apparatus or combination. Various details of method and apparatus not specified in the preceding statements will be explained further in the following description of a practical embodiment of the invention.

In the accompanying drawing, Fig. 1 is a top plan view of an unfolded composite blank shown in its initial relations to a conventional apparatus including a supporting means or platen, a defining means or templet, and folding means or infolders. v

Fig. 2 is a vertical section taken on the line 2-4 of Fig. 1.

Fig. 3, on a scale twice that of'Figs. 1 and 2,

'is a vertical section corresponding to the left side of Fig. 2, but with the material and parts in a later stage of operation. i

Fig. .4 is a partial vertical sectional view on a scale eight times that of Figs. 1 and 2 showing the composite or laminated structure of the material or blank and its initial relation to the apparatus elements.

Fig. 5 is a vertical sectional view on the same scale as Fig. 4, but showing the later or squeezing stage of the operation.

Fig. 6, on the same scale as Fig. 1, shows the completely folded blank or product in top or face view.

Fig. 7, on a scale four times that of Fig. 6, is a vertical sectional view of part of the folded product taken on the line |--'I of Fig. 6.

In the drawing, the blank B is shown in its original or raw condition in Figs. 1 and 2 and in its final or folded and fixed condition in Figs. 6 and '7. The enlarged views, Figs. 4 and 5, show that the blank is composed of a facing or lower ply b and a lining ply b, the two being combined or preattached by cement 2;. Figs. 3, 5,6 and 7 further show that the blank B comprises its main area or body portion b and its inturned or fold portion in, being usually a relatively narrow margin infolded upon the body of the blank, the extreme fold-edge or crease I; being usually somewhat sharpened by the squeezing pressure.

The cement or adhesive between the facing and lining plies, uniting them into a laminated fabric, is of a kind which is normally solid but becomes liquid under heat. It may be of a gelatinous or plastic character, or for that matter any other adhesive which answers the requirement, the heating being intended to convert it from a solid to a somewhat viscous or gummy consistency, so that it can flow within the material, but not so freely as to permeate through either portion of the facing of the folded blank, which would not merely disflgure the visible or exterior facing but would render sticky the mechanical parts and impair their operations upon the blank. An available cement is a glucose adhesive or an animal glue. Theadhesive may remain solid at room or ordinary temperatures, say from 60 to 90 F. more or less, and may only soften say between 150 and 200 F. This of course is only one example.

The method is carried out by the appliances or apparatus elements consisting of a platen or bed P for supporting the blank, the templet or defining die T for determining the shape of the folded product, and the folder or folders F movable relatively to the templet for producing the blank folds and relatively to the platen for fold-squeezing purposes.

The platen P is shown in Figs. 2 to 5 as giving support to the blank. It may for example be in the form of the conventional bed of a folding machine, and may have a raised central portion or pad p, and therebelow outward extensions p. The platen is to be kept at such a cool temperature as to maintain solid the cement, and prevent its flowing toward and into the blank facing which lies again the platen. Ordinary room temperature may constitute adequate coolness for the purpose; but since there is a tendency to accumulate heat during repeated operations, it may be desirable to form the platen with cooling means, conventionally shown as a system of fluid passages 11 adapted for the circulation of cooling water, air or other fluid through the body of the platen.

The raw blank is placed between the cool platen P and the templet T, the latter being shown in Figs. 1 and 2 as being positioned upon the blank resting on the platen. The templet constitutes a defining means which is removable or contractible out of the folds of the blank. The illustrated blank being one folded on three sides only, the templet might be extracted by bodily sliding out of the blank; but preferably the templet is of the well known contractible type, and is shown as comprising a pair of defining plates or blades F. These folders are movable relatively to the templet, or inwardly and outwardly, so as to perform the folding of the blank margins and thereafter withdraw. At the front side there is shown a gap between the two folders, making allowance for their necessary approach during folding, and this gap may be bridged, in a conventional way, by a thin plate or piece I slidable at the under side of one or both of the folders at this point. The folders may normally rest below the folding level, namely upon the platen extensions p, as shown in Fig. 2, and they may have first a rising movement to permit the inward movement, as shown in Fig. 3,- and subsequently a downward depressing movement to squeeze the folds against the platen. Mechanism to afford these motions is not shown because the same may be conventional according to long known practise, but the motions may be described by means of the motion arrows appearing on Figs. 2 to 5, wherein the arrow :1: indicates the initial rise of the folder, the arrow 11 its inward or folding movement relatively to the templet, and the arrow 2 its downward pulling action for the squeezing, creasing and fixing of the fold; these three motions being reversed to restore the foldersfor operation on the next succeeding blank.

An essential feature of this invention is the maintaining of the folders at such a warm temperature as to render liquid the cement, at least sufliciently liquid or soft for interflow between the two contacting portions of the blank lining so that they may be caused to adhere, thus fixing the blank infold portion to the body portion. Such infolder heating is itself well known for general folding purposes, and it may be performed by flowing steam through passages in the folders, but is conventionally herein shown as performed by electrical heating. Thus a series of resistance heaters H are shown, mounted on top of the infolders, approximately central thereof. These elements are indicated only diagrammatically, and the wiring is omitted since such details are well known to those conversant with electrical heating systems. Assuming that the laminated material contains a cement which liquefies at about 175 F. then the heaters H are to be operated to maintain an infolder temperature somewhat thereabove, or approximately 212 F. In a typical case heaters consuming 660 watts may serve the practical purposes hereof. These figures are merely illustrative.

- Regulation is important to keep the infolder temperature within a reasonable range, amply above the cement liquefying point to insure the described action, but not so hot that the cement will become unduly fluent and penetrate through the facing material on either the body or fold portion of the blank.- A tacky or gummy consistency permits the interflow necessary to bind together the contacting portions of the lining, while avoiding permeation of the faclns material. The regulation maybe by observation by the aid of a thermometer and a manual switch, but is preferably automatic by means of a thermostat controlling a switch for turnin on and of! the current energizing the heating coils. Fig. 1 indicates a thermostat or thermometer h assumed to extend into the body of each of the infolders. The operation is that as soon as the infolder temperature reaches the top of the predetermined range, the heating current is switched oil, and when the temperature nears the lower limit the current is again switched on. Preferably the' thermostat is of a kind'having conventional adjusting means so that it can be set to operate for any desired range of folder temperature.

The method has been sufficiently indicated to enable practice of the invention. In the abstract the squeezing step is by hot pressure against the fold, of sufficient temperature to liquefy somewhat the cement present, while applying cool resistance against the blank body. By this the softened or gummy adhesive is caused to interiiow between the two lining plies, in a direction toward the hot pressure, thus cementing together the body and overlying fold under the creasing pressure without allowing the adhesive to reach the exterior of the facing. There is a temperature gradient within the blank material from the warmest at thefolder side to the coolest at the platen. The folds are not merely creased or sharpened at the edge but are fixed across their width. By this fixation the folds in effect are plastered down upon the body, where they may remain permanently and thus obviate having loose fabric edges in the finished article.

The duration of the creasing or squeezing pressure of course will vary in coordination with the adhesive properties and the folder temperature; and as an illustrative case it may vary from somewhat less than one second to two or more seconds, more or less. It may be varied with the pressure and with the excess of folder temperature over the cement softening temperature.

What is claimed is:

The method of folding and fixing, with the aid of a supporting platen and relatively movable templet and folder, a composite blank of prefabricated limp sheet material composed of facing and lining plies mutually preattached by a cement which is normally solid at room temperature but becomes liquid under substantially elevated temperatures and to which the facing and lining are pervious; said method comprising maintaining the platen at a cooler room temperature somewhat below, while maintaining the folder at a warmer temperature somewhat above liquefying temperature of the] cement; placing the blank face down with its facing upon the cooler platen and placing the templet upon the blank lining for defining its fold; moving the warmer folder laterally inwardly to fold a portion of the blank over the templet edge, and

thereupon extracting the templet from between the body and folded portions of the blank leaving the lining portions of body and fold in contiguous face contact; and then squeezing the folded blank between the cooler platen and the warmer folder for a brief duration of substantial pressure, sufficient under such squeezing pressure to cause the folded portion to adhere tothe body portion of the blank by means of the preexisting folder-warmed liquefied cement interflowing between the contiguous lining portions, but insufficient to permit appreciable down! the cement from the lining into the facing of the blank body, whereby the exterior of the folded and fixed blank is protected from soiling by the cement.

- ALFRED G. GIIBERT. 

